Computer vision syndrome
Alam AKMS¹

Definition

According to the American Optometry Association Computer Vision Syndrome (CVS) is the complex of eye and vision problems related to near work which are experienced during or related to computer use. CVS is characterized by visual symptoms which result from interaction with a computer display or its environment. In Most cases, symptoms occur because the visual demands of the task exceed the visual abilities of the individual to comfortably perform the task. If these symptoms occur without significant usage of computer, they cannot be termed as CVS.

Introduction

The revolutionary technological advancement have made an impact in almost every aspect of our lives. Our daily tasks, office works, medical facilities, accounting, designing, database management and experimental works have all been greatly facilitated by this rapid pace of development in computer technology. The personal computer (P.C) thus become the single device which has made a great revolution in all aspect of our lives. Approximately 100 million people in the world are using computers now. In USA 71% of children work with computer in school. In India about 20 million PCs are in use. In our country computer use is increasing day by day. The cost of diagnosis and treatment of CVS in USA alone exceeds 2 billion annually which indicates a reflection of importance to think about this new emerging medical and visual problem.  

Pathophysiology

CVS is contributed by several factors:

1. Decreased blinking reflex: Studies have shown that The normal blink rate in human eyes is 16-20/min. For persons working on the computer it is decreased to 6-8 blinks/minute. This leads to dry eyes.
2. Prolonged near focusing efforts: puts strain on ciliary muscles of the eye and leads to a feeling of tiredness in the eyes. This can be a setting for early presbyopla.
3. Repeated head posture change/Fixation in a wrong posture: puts strain on the neck muscles and cervical spine.

Symptoms

Eyestrain (Non-Specific Ocular Discomfort), fatigues, headache, blurred near vision, blurred distant vision, dry or irritated eyes, neck pain and/or backaches, diplopia (Double vision), difficulty in re-focusing the eyes.

Visual/ocular signs

Accommodative disorders, early presbyopia, binocular vision dysfunctions, Refractive Errors: Hyperopia-astigmatism-myopia, dry eyes, conjunctival, congestion (Redness).
CVS associated musculo-skeletal disorders- Cumulative Trauma Disorder (CTD) or Repetitive Strain Injury (RSl): Carpal tunnel syndrome, bursitis, neck tension syndrome (Muscle strain), tendon disorders- De quervain’s disease, tenosynovitis- trigger finger.

Environmental factors of computer workstations

Contrast and resolution of the display, viewing distances and angles, adjustability of workstation, room lighting, sustained viewing.

Relationship of CVS to RSl or CTD (Musculoskeletal disorders)

Symptoms are work related and associated with repetitive activity. Problems are related to disorders of muscles, tendons, bones, or nerves. Problems occur or are aggravated by repeated movements. A lengthy period of time is required for the problems to develop and for the individual to recover.

Diagnostic tests

Tear film Break-up time (TF-BUT): Examined under slit-lamp with a red free light. -Fluorescein dye is used. -Normal- >10 seconds.
Schirmer Test-1. -Special graduated paper strip is used. -Normal value- >10mm in 5 minutes.
Rose Bengal Staining. -To detect corneal and conjunctival epithelial defect in dry eyes. –A positive result is highly significant for CVS.

Management

Proper History

Symptoms-duration, aggravating and relieving factors. -Nature of work, Computer exposure time. -Existing workstation setting-Fumiture, lighting, etc. -Per-existing ocular or musculoskeletal diseases. Examinations. -Refractive status-near, intermediate and distant. -Ocular motility-Versions and Vergence. -Thorough neuromuscular work-up.

Differential Diagnosis

1. Cervical spondylitis
2. Migraine
3. Anxiety Neurosis
4. Dry Eye Syndrome

Investigations

1. X-ray of cervical and lumbo-Sacral spine for exclusion of preexisting spinal disease
2. TF-BUT. -Schirmer-1.
3. Rose Bengal test.

Treatment

A. Counseling regarding

1. Awareness building
2. Work Environmental modification

A. Counseling: 10 steps for relieving computer Eye strain:
1. Get a computer eye exam. Before start using computer. Repeat once a year.
2. Use proper lighting. Eliminate exterior light by closing drapes, shades or blinds. Reduce interior lighting by using lower intensity bulbs and tubes.